Stop collar



Sept. 5, 1961 K. A. WRIGHT ET AL 2,998,848

sToP COLLAR Filed Nov. 4, 1957 2 Sheets-Sheet 2 2,998,848 STOP VCOLLAR Kenneth A. Wright and James 'R. Solum, Los Angeles, Calif., assignors, by mesne assignments, to B and W, Incorporated, Torrance, Calif., a corporation of California Filed Nov. 4, y1957, Ser. No. 694,263

8 Claims. (Cl. 166-241) t This invention relates to the art of drilling wells and producing iiuid therefrom and is particularly directed to an improved form of stop collar for use with casing or other well pipes. This invention relatesr to improvements over the invention disclosed in our copending application Serial No. 550,597, now Patent No. 2,872,226 led December 2, 1955 for Stop 'Collar For a Well Pipe.

Present day alloy steel casing and other well pipes cannot readily be welded in the iield because of possible damage to the pipe. Accordingly, when it is desirable for any reason to mount a stop collar on the outer surface of the casing or other well pipe, the stop collar must be anchored in place by means other than welding. Moreover, it is often important that the radial thickness of the stop collar assembly be held to absolute minimum and that passage area outside the casing or other pipe be restricted as littlef as possible. The problem is complicated by the fact that commercial mill tolerances on casing and other well pipes permits considerable variation in outside diameter of the PIPC- In accordance with our invention, we'provide a stop collar assembly which requires no welding on the pipe, which has minimum radial thickness and presents a minimum ofobstruction to passage of iluids outside the well casing or other pipe, and which will accommodate yariations in outside diameter of the pipe. 'y g y In accordance with vour'invention, we" provide an annular collar having a series of circumferentially spacedy pockets formed inthe inner surfaceV thereof. vPairs of wedge elements are mounted in each of the pockets and an integral looped strap or web connects eachpairv of separate the wedge elements and move them along vin-v clined surfaces in the pockets into pipe gripping position. The outside surface ofthe collar between the pocket locations is cylindrical and' hence offers a minimum of Aresistance to the passage of fluid within the well and outside the annularvcollar. Other objects andadvantages will appear hereinafter. I'

In the drawings: FIGURE l is a perspective view showing a preferred embodiment of our invention. FIGURE 2 is a plan view partly broken away taken substantially on the lines 2.--2 as shown in FIGURE 1.

' FIGURE 3 is a sectional side elevation taken substantially on' the lines 3 -3 as shown in FIGURE 2.

f FIGUREA isv a sectional on lines 4-4 as shown in FIGURE 3. n

FIGURE 5 is a sectional view similar tol FIGURE 3 showing the wedge elements in pipe-gripping position.' l

plan view taken substantially sembly 10 includes an annular. collar 11 having aplural-l ity .of circumferentially spaced pockets 12 provided onf the inner surface'13 thereof.A The material comprising; the collar issubstantially uniform in'thickness,V .thereforev in forming the'internal pockets v12 the external ribs 26 arel also formed. The pockets 12v are identical 'and each reaches its maximum radial depth at alocation midway.k

between the upper and lower ends of the collar.r Each' pocket is formed by pairs of at'tapering surfaces T14 which merge with the cylindrical inner periphery 153 .of the collar 11 at locations near the upper and lower ends of the collar.

Each pocket 12 is providedwith a central axially extending window opening 15. An offset web 16 projecting` radially outwardly from the opposed wedge elements 17 and 184is received within the pocket 12. The wedge clef ments 17 and 18 and the connecting web 16 comprise a double wedge member generally designated 19 and this member is substantially the same as that shown and described in our copending application entitled Stop Collar For a Well Pipe filed December 2, 1955, Serial No.

The double wedge members 19 are initiallyv held' in,V position within the pockets 12 by means of staking indexi-4 tations 23 applied to the outer surface of the collar'lll adjacent the window opening 15.

In use, the stop collar assembly 10 is slipped over the"v end of a well pipe and moved along the length thereof to the desired location. A hammer or similar t'ool is `then used to apply radial blows to the projecting portions of the web 116 thereby driving the wedge elements 17 and 18l longitudinally in opposite directions from the retracted position shown in FIGURE 3 to the pipe-engaging posi tion shown in FIGURE 5. The stop collar assembly 10 is then rigidly xed to the outer surface of the pipe 22. When `thurs iixed in position, radial thickness of the as` sembly 10 remains at a minimum and flow channels 24 for` fluidare defined in the circumferential space outside the annular collar 11 and between each pair of ribs 26.v The stop collar assembly 10 thus forms only a minimum` obstruction to ilow of fluid outside the well pipe 22. M

' Infthernodlied form of our invention shown i-n FIG` URE 6, the `stop collar assembly 10a is substantiallythe same -as that previously described except that the collar 11a is formed in two semi-circular parts connected by? 4separable hinge elements 27 and 28, and hinge pins 29.*

. In this form of our invention, the stop collar assembly' FIGURE 6 is a perspective view similar tol-TIGUREjl showing a modification.

FIGURE 7 is a side elevation showing another modiiication. I

FIGURE 8 is a sectional elevation taken substantially on the `lines SS as shown in FIGURE 7, n i' FIGURE 9 is a sectional detail taken substantiall the lines 9- 9 as ,shown in FIGURE 7.

,FIGURE l0 is aperspective view ofone of the wedge elements. 4 j Y Referring to the drawings, the annularstop collar` asabove.

In the modi-fied form ofour invention shown in FIG-``I URES 7, 8 and 9,- the stop collar assembly 10a is em ployed yas one of the axially spaced collars. The cent-ralf'j izer generally designated 30 includes the stop collar 10d,

the plain collar 31 and a plurality of outwardly bowed leaf spring elements 32. These lbow springs 32 vmay be welded -at their ends to the adjacent ends of the collars 10a and 31, as shown iat 33. The plain collar is provided with' hinge assemblies 34 which are axially aligned with the hinge pins 29 von the stop collar 10a, thereby permitting the` centraliz'er 30 to be applied laterally to the pipe.

Since theplain collar '31 is notprovided with y or wedge members it presents a bare of obstruc-V tion to fluid flow outside the wellpipe.

Patented Sept, 54,

, 3 the bow springs 32 are aligned with the external radially projecting ribs 35 which enclose the pockets and wedge elements on the stop collar a. The channels 25 on the outer surface of the stop collar 10a between these ribs 3S (which correspond to the channels 24 of the first destructure) are thus aligned with the spaces between the bow springs 32 and hence flow of fluid through thesechannel's and spaces is substantially unimpeded.

Having fully described our invention, it is to be understood that we do not wish to be limited to the details herein set forth, but our application is of the full scope of the appended claims.

We claim:

-1. In a collar assembly for installation upon a well pipe, the combination of a collar of substantially uniform wall thickness having a series of circumferentially spaced pockets extending radially outwardly from the inner surface thereof the material of the collar overlying said pockets being substantially equal in thickness to the thickness of the remaining portion of the collar, each pocket having oppositely tapered internal surfaces yand a window openingextending ltherethrough between said tapered surfaces, and a plurality of members positioned in said pockets, each member having two wedge elements connected by means protruding through each window opening, the wedge elements engaging the tapered surfaces, whereby said wedge elements may be moved away from each other along said tapered surfaces b y -applying a force against said protruding means and thereby anchor the collar upon the well pipe.

v 2. In a stop collar assembly for installation upon a well pipe, the combination of: a collar having a series o f circumferentially spaced pockets extending lradially outwardly from the inner surface thereof, each pocket having oppositely tapered internal surfaces and a centrally positioned window opening of lesser width than said pockets extending therethrough and symmetrically located with respect to said tapered surfaces, a plurality of members each having two wedge elements connected by a relatively narrow web protruding through each window opening, the wedge elements engaging the tapered surfaces. p

3. In a stop collar assembly for installation upon a well pipe, the combination of: a collar substantially uniform in wall thickness throughout and having internally a series of circumferentially spaced pockets extending radially outwardly from the inner surfacethereof, the surface of said collar externally of said pockets also extending radially outwardly to form external ribs coextensive with said pockets, the collar being substantially cylindrical at locations between the ribs to provide flow channels for fluid outside the pipe, each pocket having opposite tapered internal surfaces, each pocket also having a centrally positioned window opening of relatively narrow width extending therethrough and symmetrically located with respect to said tapered surfaces, and a plurality of members in said pockets each having two wedge elements connected by a web of relatively narrow width, each web protruding through one of said window openings.

4. In a stop collar assembly for installation upon a well pipe, the combination of: a collar having a series of circumferential'ly spaced pockets extending radiallyf outwardly from the inner surface thereof, each pocket having oppositely tapered internal surfaces and a centrally positioned window opening substantially narrower than said pocket extending therethrough and symmetrically located with respect to said tapered surfaces, ta plurality of members each having two wedge elements connected by an integral relatively narrow offset web, each wedge element having one portion for engaging one of the said Itapered surfaces and having another portion for ccntactingthe well pipe, said wedge lelements initially extending axially in `said pockets and clearing said pipe tdi-permit slidinglof` saidcollar thereon with the offset webs disposed between said wedge elements protruding through said window openings, whereby said wedge elements may be moved away from each other along said tapered surfaces by applying a force against said offset webs, and thereby anchor the collar upon the well pipe.

5. In a device for installation upon a well pipe, the combination of a pair of axially spaced collars connected by a series of axially extending bow springs, one of the collars being uniform in wall thickness and having a series of circumferentially spaced pockets extending radially outwardly from the inner surface thereof, and forming externally corresponding ribs, each pocket having oppositely tapered internal surfaces and a window opening extending therethrough, each bow spring being aligned with one of said ribs so that flow channels are defined outside the collar between each pair of ribs to provide a minimum obstruction to fluid tlow, and wedge means in each of said pockets including actuating means protruding through the window openings for securing said collar upon a pipe.

6. In a device for installation upon a well pipe, the combination of: a pair of axially spaced collars connected by a series of axially extending bow springs, one of the collars being uniform in wall thickness and having a series of circumferentially spaced pockets extending radially outwardly from the inner surface thereof and forming externally corresponding ribs, each pocket hav- Ving oppositely tapered internal surfaces and a window 7. A collar assembly for installation on `well pipes,.

comprising: a cylindrical collar member having relatively thin walls, the material of the collar member extending outwardly `to form externally a plurality of spaced ribs dening therebetween a plurality of flow channels, said ribs forming interiorly a plurality of shallow pockets,`

each having opposed axially tapering surfaces and a. window opening extending therethrough; opposed Wedge elements within said pockets initially approximately filling said pockets and conforming thereto; and means initially extending through said window opening for translating said wedge elements away from each other without distortion to lock said collar to a pipe extending therethrough.

8. Means for installation upon a well pipe, comprising: a pair of axially spaced collar members having relatively tbin walls; a plurality of axially extending bow springs connecting said collar members; the material of at least one of said collar members extending outwardly to form externally a plurality of ribs in alignment With said bow springs, said ribs and bow springs forming flow channels therebetween, said ribs forming interiorly a plurality of shallow pockets, each having opposed axially tapering surfaces and a window opening extending therethrough; opposed wedge elements within said pockets initially approximately filling said pockets and conforming thereto; and means initially extending through the said window opening for translating said Wedge elements away from each other without appreciable distortion to locksaid collars and connecting bow springs onto a pipe extending therethrough.

References Cited in the file of this patent UNITED STATES PATENTS 465,202 Preston Dec. 15, 1891 :1,812,945 Granger July 7, 1931 1,997,649 Ohlund Apr. 16, 1935 2,368,737 Badgley Feb. 6, 1945 2,628,682 Wright Feb. 17, 1953 2,812,200 Yeargan Nov. 5, `1957 

